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We report some computational results obtained by using the phase field model for binary alloy solidification. We study directional solidification and concentrate on the transition between a planar interface and steady shallow cells near the onset of morphological instability at low growth speeds. The model is formulated on the principle of local positive entropy production. This gives rise to a set of partial differential equations for the temperature, composition and the phase fields. We make a frozen temperature approximation and compute steady-state nearly periodic cellular crystal–melt interfaces in two dimensions. The cell shapes can be characterized by a small number of Fourier coefficients and become nearly sinusoidal as stability is approached. Wavelength selection by tip splitting or coarsening is also observed.

A single industrial robot is sometimes not sufficient to achieve some complex tasks such as polishing or welding on complex surfaces. In this case, a positioner is usually employed as an auxiliary device, and their motion is required to be coordinated. This paper proposes a method for coordinated motion planning of a manipulator-positioner system which consists of one 6-DoF manipulator and one 2-DOF positioner. A coordinated kinematics model of the manipulator-positioner system is first established. Three-points calibration for the relative position of the positioner with respect to the manipulator is then presented. Complex paths are planned with AutoCAD and transformed into robotic language by an offline programming system. Finally, experiments in which writing letters on the moving plate of the positioner are conducted to verify the feasibility and effectiveness of the presented coordinated motion planning method and the offline programming system.

We develop a rather general thermodynamically consistent phase-field model for solidification of a binary alloy, based on an entropy functional that contains squared gradient terms in the energy density, the composition and the phase-field variable. By assuming positive local entropy production, we derive generalized phase-field equations for an alloy, including cross terms that connect thermal and compositional driving forces to energy and solute fluxes. We explore this model in detail for a regular solution and show that four existing models can be recovered as special cases. We also use it to develop a new phase-field model for an alloy in which an explicit phase-field variable is absent.

To carry out automatic line inspection, a novel modular miniature wire inspection robot with multiple locomotion modes, called MiniWirebot, has been developed. Developed by modular method, the robot consists of six joint modules, two grippers and three wheels assembled into four legs symmetrically. Two opposite 2-DoFs legs with gripper modules at the ends are utilized for climbing, while other two 1-DoF legs are equipped with wheel modules for rolling locomotion. With this configuration, MiniWirebot achieves outstanding mobilities including rolling on the floor or along a line, climbing poles or lines, transiting among the floor, poles and lines, and so on. In this paper, we present the development, show the prototype and illustrate the multiple locomotion of MiniWirebot. Inspiration and motivation of the development of the robotic system are introduced first, followed by the analysis of grasping force to ensure climbing safety and the inspection procedure. A series of experiments are conducted to verify the feasibility and effectiveness of the proposed miniature robot and the analysis.

Background We present an analysis of the utility of multispectral versus standard RGB imagery for routine H&E stained histopathology images, in particular for pixel-level classification of nuclei. Our multispectral imagery has 29 spectral bands, spaced 10 nm within the visual range of 420–700 nm. It has been hypothesized that the additional spectral bands contain further information useful for classification as compared to the 3 standard bands of RGB imagery. We present analyses of our data designed to test this hypothesis. Results For classification using all available image bands, we find the best performance (equal tradeoff between detection rate and false alarm rate) is obtained from either the multispectral or our "ccd" RGB imagery, with an overall increase in performance of 0.79% compared to the next best performing image type. For classification using single image bands, the single best multispectral band (in the red portion of the spectrum) gave a performance increase of 0.57%, compared to performance of the single best RGB band (red). Additionally, red bands had the highest coefficients/preference in our classifiers. Principal components analysis of the multispectral imagery indicates only two significant image bands, which is not surprising given the presence of two stains. Conclusion Our results indicate that multispectral imagery for routine H&E stained histopathology provides minimal additional spectral information for a pixel-level nuclear classification task than would standard RGB imagery.

The authors discuss the use of digital filtering and spectrum estimation techniques for improving the efficiency of the finite-difference-time-domain (FD-TD) algorithm for solving eigenvalue problems. It is demonstrated by means of numerical results that the efficiency of the FD-TD method for dielectric resonator analysis has been improved by at least one order of magnitude, without any loss of accuracy in calculating the resonant frequencies. This new result makes it possible to use the FD-TD method as a practical design tool for dielectric resonator analysis. >

An efficient finite difference time domain method, coupled with digital filtering and spectrum estimation techniques, was used to analyze the resonant frequencies and field distribution of two resonant structures of practical importance. The semiconductor-dielectric multilayer resonators, which are important in optically controlled circuits, were analyzed, and found to be in reasonable agreement with the experimental results. The results of a practical tuning screw dielectric resonator are also given and compared with the available rigorous results. >

To determine the state of anti-tuberculosis drug resistance, and to analyze the trend of drug resistance rate and assess its impact on National TB Programme (NTP).392 Mycobacterium tuberculosis (MTB) isolates from a nationwide epidemiological survey were subjected to susceptibility testing against 6 anti-tuberculosis drugs using the absolute concentration method.The resistant rate to any drug was 27.8% in all MTB isolates, 18.6% in 263 new cases and 46.5% in 129 previously treated cases. Multi-drug resistant rate (MDR) was 10.7%. Initial and acquired MDR was 7.6% and 17.1%. Any resistance to INH, SM, RFP, PAS-Na, EMB and TB(1) was 17.6%, 17.3%, 16.6%, 2.8%, 1.5% and 1.3%, respectively. The resistant rates to 1, 2, 3 and 4 or more drugs were 7.6%, 4.6%, 4.6% and 1.9% in new cases and 14.7%, 19.4%, 10.1% and 2.3% in previously treated cases. The initial drug resistant rate did not show significant difference (P0.05) among different sex and age groups.Compared to the previous data, the total drug resistance and initial drug resistance decreased significantly, but were still high. More attention should be paid to the trend of resistance of MTB to first-line drugs and especially the high incidence of MDR-TB.

Skewed distributions appear very often in practice. Unfortunately, the traditional Zipf distribution often fails to model them well. In this paper, we propose a new probability distribution, the Discrete Gaussian Exponential (DGX), to achieve excellent fits in a wide variety of settings; our new distribution includes the Zipf distribution as a special case. We present a statistically sound method for estimating the DGX parameters based on maximum likelihood estimation (MLE). We applied DGX to a wide variety of real world data sets, such as sales data from a large retailer chain, us-age data from ATT in all cases, DGX fits these distributions very well, with almost a 99% correlation coefficient in quantile-quantile plots. Our algorithm also scales very well because it requires only a single pass over the data. Finally, we illustrate the power of DGX as a new tool for data mining tasks, such as outlier detection.

The dispersive absorbing boundary condition (DBC) developed in [1] for microstrip component analysis, a case where dispersion is week, is now applied to a strongly dispersive case which occurs in conductor waveguides. The absorbing quality of the DBC is found to be much superior to that of the absorbing boundary conditions that are currently used for waveguide component analysis. Due to the significant performance improvement and the easy implementation of the DBC, the accuracy and the efficiency can be improved greatly when applying the boundary condition to waveguide component analysis.